Will the new 70-200 2.8 IS have a more consistent focus across the zoom range?

My current 70-200 2.8 IS needs -10 focus microadjustment at 70 mm, but +5 at 200mm. So it's essentially one or the other. Not great. I wonder whether Canon has improved focus consistency across the zoom range of this lens in the Mark II version. That would be a pretty good reason for me to upgrade.

2010-06-18: SEE UPDATE BELOW

...or have the body correlate MA and zoom. This would be a neat feature for Canon to give us.

I think you're likely to see the same thing you do now with the 70-200s: Variation.
One may be perfect, while the next will need +10, while the next will differ throughout the zoom range.

RWatkins wrote in post #9510885
...or have the body correlate MA and zoom. This would be a neat feature for Canon to give us.

This seems a bit too tricky. I don't see the sensor moving back and forth as you zoom in and out. But stranger things have happened ...

Incidentally, does anyone know whether different MAF settings can be registered under the C1, C2, C3 positions? That would be one possible way out ...

EDIT: I tried this and failed. I could not register a different MAF value in the C positions, even though the manual says —on p. 224— that Custom Functions are registerable.

The sensor doesn't move in and out for microadjustment; it is a correction to the autofocus values transmitted between the body and the lens. It should be simple for Canon to program it so it is also focal length aware on a zoom.

TheHoff wrote in post #9511245
The sensor doesn't move in and out for microadjustment; it is a correction to the autofocus values transmitted between the body and the lens. It should be simple for Canon to program it so it is also focal length aware on a zoom.

Right, thanks for clarifying this. I wonder whether this could be taken care in a firmware update ...

My lens is still under warranty. Anyone knows if there is some type of calibration that Canon service could do to remedy this?

My 70-200 is now with Canon for calibration of its (uneven) focus. Will report on this as soon as I get it back. Fingers crossed.

Did Canon charge you for the calibration or was it under warranty? I am continously tweaking my micro-adjustment on this lens. My 24-70L is spot on but I really struggle with this one and have been wondering if it is in need of calibration.

A proper focusing zoom like the 70-200mm I presume should focus throught the entire focal range properly.

My 70-200 F4 and 24-105 F4 IS does.

I had to send in my 28-135mm, 2 times to correct a focus shift from 70-135mm. Between 28-70 it would focus dead center where I set it and from 70-135 it would slightly drift front focus.

Now after calibration its dead center throught the focal length.

My Tamron 17-50mm had focus issues that up to 5 feet would be fine and then front focus at futher distance. After 2 calibration it was better but at 17mm I noticed that it was dead on and front focus from 24-50mm.

After I spoke to the tech exactly what the problem was he understood and siad that could be fixed. I sent in my 50D with the lens set at 0ma. He was able to correct it that between 17-50 it focus dead center at 0ma.

Im very happy with the performance of the 70-200, but if the new 70-200 F2.8 IS II as they say is better optically plus the stabilizer performance of the F4, I think I might upgrade despite the weight. The weight was what holding me back from buying the 2.8 IS.

Socrates99 wrote in post #9652371
Did Canon charge you for the calibration or was it under warranty? I am continously tweaking my micro-adjustment on this lens. My 24-70L is spot on but I really struggle with this one and have been wondering if it is in need of calibration.

It's still under warranty. I haven't picked it up yet, but they took copy of my receipt and gave (so far) no signals that I may be charged. I'll find out soon.

I am happy to report that the lens came back from Canon with a nice an uniform focus. MAF at -1 makes it perfect from 70 to 200mm. Worth while sending it in!

cfibanez wrote in post #9510823
My current 70-200 2.8 IS needs -10 focus microadjustment at 70 mm, but +5 at 200mm. So it's essentially one or the other. Not great. I wonder whether Canon has improved focus consistency across the zoom range of this lens in the Mark II version. That would be a pretty good reason for me to upgrade.

sorry to ask but,how do u know it needs the adjustment and how do u find that out?

something-wild wrote in post #9809904
sorry to ask but,how do u know it needs the adjustment and how do u find that out?

I was about to ask the same thing, some of you guys just are so into this stuff!

something-wild wrote in post #9809904
sorry to ask but,how do u know it needs the adjustment and how do u find that out?

You shoot to one of the many targets available for focus tests (I use THIS ONE) at 25 to 50 times the focal length; camera on tripod, remote shutter release, mirror lock-up, etc.. Change MA settings on your camera to cover all the range as much as possible taking shots at different intervals (I do a first series at intervals of 5 units MA, i.e. -20, -15, -10 ... all the way to +20). You look then for the best focus in your monitor at 100% magnification. You figure out which MA settings fits best your lens, This is a rather common problem with zooms. I re-did the test after my lens came back from Canon and I was very impressed. The huge difference that was previously present between the wide and long ends disappeared!

cfibanez wrote in post #9831569
You shoot to one of the many targets available for focus tests (I use THIS ONE) at 25 to 50 times the focal length; camera on tripod, remote shutter release, mirror lock-up, etc.. Change MA settings on your camera to cover all the range as much as possible taking shots at different intervals (I do a first series at intervals of 5 units MA, i.e. -20, -15, -10 ... all the way to +20). You look then for the best focus in your monitor at 100% magnification. You figure out which MA settings fits best your lens, This is a rather common problem with zooms. I re-did the test after my lens came back from Canon and I was very impressed. The huge difference that was previously present between the wide and long ends disappeared!

thanks